I'm trying out Linux by installing openSUSE 12.2 x64 on VirtualBox; the host is 64 bit Windows 7 Ultimate. I gave the install 16GB of storage - I will only be messing around with it - I thought this should be plenty. By default, Virtual Box splits the storage you give it roughly in half - giving half to the rootfs and about half to user space.

I've figured out via previous attempts that when the rootfs partition gets full - nothing works. But I've hardly done anything with it - I've installed Linux, run some updates and haven't even installed any extra software. I'm seeing that my rootfs is filling up fast - 83% already with no extra software installed - and hardly anything is going to my other partition (/home).

Is this expected behavior? Does all installed software get installed to the rootfs? I've heard you should try to keep rootfs as small as possible, but all I've done is install Linux and update the system and it's at 4.8 GB - 83% full.

How can I keep my rootfs from filling up? Should I have adjusted the VirtualBox defaults to just make rootfs bigger?

Here's the results from a df: Notice how the /dev/sda3 is hardly used.

It's not VirtualBox which sets the partition sizes, it's openSUSE. Could you add the output from df, and mount to your query.
–
EightBitTonyOct 23 '12 at 8:35

6GB for the OS and applications (Linux doesn't distinguish between the two) isn't very large nowadays. It's enough for a basic installation, not if you want to try out a lot of programs. Keeping the root filesystem small is not really a concern nowadays.
–
GillesOct 23 '12 at 22:00

Thanks all for the informative answers. It's helpful to know how to track down what is taking up the space, but what I was really trying to ask is "should my rootfs be filling up so quickly/am I doing something wrong when installing? Or is this expected and appropriate behavior in Linux for installed programs to go in the rootfs?"
–
JasonKNov 6 '12 at 5:06

It could be that it is the cache of the package manage that fills up the rootfs. That what happens to me all the time. For zypper it should be located under /var/cache/zypper/RPMS.
You should be able to clean the cache by running zypper clean.

I don't use OpenSuse so I'm not sure about this because from a quick google there seems to be some dispute about zypper having a cache...